The present invention, an apparatus for automatically centering and clamping a rotatable information recording disk in a data storage device, relates to the field of information storage device disk-handling systems, and in particular to systems for automatically centering and securing said disks in data storage devices having removable disk capabilities.
Rotating disk storage systems can be divided into two broad categories, those which have user-replaceable information disks and those which have permanently mounted disks. One of the advantages of a replaceable disk system is that the disks of a given system are compatible and therefore usuable in all the disk units in that system. That is, not only can the disk be installed and removed any number of times on a given disk system, it can also have data recorded on it while installed in one system and be removed and installed in a different system where the data can be read. When a replaceable disk is mounted on the spindle, it is essential that the disk be accurately centered on the axis of rotation of the spindle in order to prevent read and write errors.
In modern magnetic and optical data storage systems, it is desirable for the customer to be able to remove a given disk from the system and insert a new disk to be read or written upon. Because of the relatively minute distance between tracks on both magnetic and optical disks, precise centering of the newly inserted disk is desirable. In particular, because the separation between tracks on optical disks is in the order of a few microns, proper centering of the disk on the spindle of the optical data storage device is especially critical. In the prior art, a wide variety of means are known for mounting and securing removable disks. Optical recording devices require even more accurate centering of the disk than in prior art devices because of the smaller spacing between optical data tracks. One basic requirement of securely fixing the disk to the spindle in order that the disk remain securely fastened to the spindle during the rapid rotation of the disk during operation. The disk may also stay severely fastened to the spindle if an unusual power interruption occurs. In the prior art, the features which provide for attachment of the disk to the spindle during operation, have caused a loss of centering accurately due to the high friction between disk and spindle during the centering process. The present invention addresses these problems by providing a means for accurately centering the disk on the spindle prior to clamping, and only when accurate centering has been achieved, then securely fixing the disk to the spindle for rotation.
Another problem with the prior art is that even though the disk is rigid, the unsupported portion of the disk will "flutter", or "wobble", as a result of the resonances and vibrations causes by the moving mechanical assembly and of the air currents produced by the rotation. This wobble causes the surface of the disk to move toward and away from the magnetic heads or optical lens, increasing and decreasing the strength of the signals recorded or read in a magnetic recording and causing defocusing of the radiation beam in optical recording.
The disclosed invention is also an improvement over the prior art in that a relatively simple centering and clamping apparatus is disclosed.
It is an object of this invention to provide a means for the accurate centering of a disk to a spindle in a data storage device.
It is a further object of the disclosed invention to provide a means for the accurate repeatable centering of a disk on a spindle in a data storage device.
It is still a further object of the disclosed invention to provide a means for securely and safely clamping a disk to a spindle in a data storage device.
It is still yet a further object of the disclosed invention to provide a means for relatively simply securing and clamping a disk to a spindle in a data storage device.